窗口之间的PyQt5关系，首先不会关闭

from PyQt5.QtWidgets import QApplication, QMainWindow, QDialog

class MyWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.setWindowTitle('Main Window')
        self.setGeometry(100, 100, 400, 300)

    def closeEvent(self, event):
        # 确保调用父类的closeEvent
        super().closeEvent(event)
        print("Main window closed")

class ModalDialog(QDialog):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setModal(True)
        self.initUI()

    def initUI(self):
        self.setWindowTitle('Modal Dialog')
        self.setGeometry(150, 150, 300, 200)

    def closeEvent(self, event):
        super().closeEvent(event)
        print("Modal dialog closed")

if __name__ == '__main__':
    app = QApplication([])
    main_window = MyWindow()
    modal_dialog = ModalDialog(main_window)
    main_window.show()
    app.exec_()